Laelia with white sunken stain on leaf

[Roma Oli]

Hello,

I purchased a Laelia purpurata a few weeks ago. It is one of my first orchids and the first of this kind.

Soon after, a stain on a leaf appeared - in the beginning, it was brownish and in a week it became whitish. The surface is dry and sunken, there's almost no discolouration on the other side of the leaf. Do you know what it is? Cold damage? Since I have other orchids, I am worried it is contagious.

Apart from that, today I noticed translucent spots on the new growth (honeydew?) and a weird green bubble on the root. Pseudobulbs were plump and became shrivelled too.

I am going to repot it as soon as possible. If anyone has any advice on how to tackle these issues, I would very much appreciate it.

Thanks!

[SouthPark]

The good news is that it is dry and sunken. So the orchid has probably recovered from whatever caused it.

The thing to do now is - give it medium level lighting, and no direct intense sunlight for now.

And give it a nice temperature range to grow in - not too cold. And also give some good air-flow in the growing area.

Also make sure that the media is airy enough in the pot - so that air can easily flow through the media and pot. This also means make sure the plastic pot has some decent sized drainage holes.

The round translucent thing hanging off the side of the root doesn't look right. I don't think laelia/cattleya roots normally develop round things like that. Keep an eye on it - in case it's something else. Also has the appearance of one of those slow-release fertiliser ball things (that look like that when they become wet).

[aliceinwl]

Where are you growing? Did the pale area appear suddenly? I’d say either sunburn or some type of critter eating the top layer of tissue. The blob also looks like it could be a fertilizer ball to me. In terms of pseudobulb wrinkling, you may need to look at your watering frequency. Depending on your conditions, it might need a fair amount of water. I have some similar sized plants in similar substrate and pots on a southern windowsill and I’m watering about every other day.

[Roma Oli]

Thank you so much @SouthPark and @aliceinwl for advice.

I feel better about the leaf condition. When I bought the orchid (2 weeks ago), the leaf looked quite ok to me (it might have been slightly discolored but I didn't think it was a problem), then in 3 days I noticed discoloration - in the begining I was doubting about the color - it looked brownish to me and later became whitish.

I am growing it in my studio apartment in San Francisco. It gets a lot of southeast sun and I use window shades to diffuse it. I will keep it away from the window for now. I usually water my orchids once a week, so I should definitely give it more water then.

I removed the orchid from the pot today and found out that the weird round thing was a fertilizer ball - there were many other balls in the pot.

I removed some roots as they were mushy and the orchid got divided in two parts which is probably not good. The media seemed very good to me and I was about to put it back but then I noticed several caterpillars in it and some other very fast moving tiny bug.... So I got rid of the media, cleaned the orchid with hydrogen peroxide.

I am not sure how to make sure there are no eggs on the orchid remaining - if cleaning it with hydrogen peroxide is enough or I should do something else.

[SouthPark]

Nice work in discovering caterpillars in the media.

One nice recommendation is to avoid using hydrogen peroxide on roots - that's if you did use it on roots. The hydrogen peroxide can set orchids back, as it probably harms some little natural hairs (which can be too small to see sometimes) that are part of the roots.

The divided orchids look just fine. Just need to get a pot that has good size drainage holes. If your existing pot has small drainage holes, or not enough of them, then I would just use a cheap soldering irons to burn more holes in the bottom, or make holes bigger.

What sort of media have you got access to? Are you able to get scoria? Or maybe orchiata bark? For the roots you have right now, which look good, I'd just pop the plant into a pot with scoria pieces of average diameter 5 mm. When your plants get larger, you can eventually progress to larger pieces of scoria (eg. 10 mm diameter) - and a larger pot.

Since you grow your plant indoors, and since there caterpillars, it should be ok to spray the media with a little bit of ----- not sure if you have it available ---- imidacloprid.

On the other hand - if you've given the roots and stem a nice wash with room temperature water, then I think you should be ok. Most likely have washed everything off already.

[Orchid Whisperer]

I agree with the recommendation to never use hydrogen peroxide on roots, or to "treat" potting medium that has a plant growing in it. This is potentially deadly to the orchid.

[aliceinwl]

The caterpillars are probably responsible for the leaf damage. Even 3% hydrogen peroxide can cause tissue damage. If you only applied it to the media, I’d think you could re-use since it degrades into water.

Given that Cattleya types don’t take well to root disturbance and especially if you did treat the roots with hydrogen peroxide, I’d recommend getting some Kelpmax. I’ve had very good luck using this to jumpstart new root growth in my plants. I’d also stake the plants if they show any tendency to wobble when repotted.

I have a couple L. pururata crosses and they’re pretty vigorous growers so I think the prognosis for yours is good.

[Roma Oli]

You are right - I shouldn't have used hydrogen peroxide. What I did was washing it carefully with lukewarm water and spraying with hydrogen peroxide. The roots do not look as healthy as before and the pseudobulbs became wrinklier.

I have a few oncidium orchids and I used hydrogen peroxide repotting them a year and a half ago (after removing dead roots). They were fine afterwards.

I am getting a mix of Medium Orchiata Monterey Pine Bark, Large Sponge Rock, Hydroton, Medium Stalite. It is a cattleya/laelia mix according to the label. Looks similar to me to what it was planted in originally. The pot doesn't have holes on the sides but it is almost completely open at the bottom. I ordered Kelpmax - hopefully, it arrives soon enough and helps to recover. It has great reviews - haven't heard about it before - the content looks very different from my fertilizer.

Thank you so much for your advice.

[aliceinwl]

I’d repot it as soon as you get the media. If it’s going to be awhile before you get the media maybe try to spag & bag method to slow water loss (damp not wet sphagnum moss in a clear bag with the plant). Your pot sounds good for reuse. I’d try to just give it bright diffuse light until it has regrown some roots.

Once you get the Kelpmax the dilution for orchids is 1 tablespoon per gallon. If the plant isn’t potted soak it bareroot overnight. If it is potted, soak it in pot overnight. Once you’ve done the initial soak, you can use the solution monthly (there can be too much of a good thing and using it too often can lead to problems). My rootless Cattleyas that I did a Kelpmax soak on started pushing new roots in about 2 weeks.